The switching on of cell-death signalling by the application of an external magnetic field is demonstrated both in vitro and in vivo in a study published online this week in Nature Materials. This ability to control the switching on of programmed apoptosis - cell death - in a selective manner may have important implications in cancer therapy.

Jinwoo Cheon and colleagues created zinc-doped iron nanoparticles with antibodies attached that target cell-death receptors and promote apoptosis signalling pathways when magnetically activated. The authors found that these antibodies bind to complementary receptors that are highly expressed on cancer cells; subsequent switching on of the magnetic field causes death-receptor clustering, and thus initiates apoptosis. Such magnetic control is also indicated by morphological changes that are known to be characteristic of apoptosis in the tail region of zebrafish, a standard in vivo model for vertebrate systems.

In a broader setting, the authors note that this method of controlling a cellular process using a magnetic switch could be applied to cellular functions for which the pathways are mediated by the clustering of surface-membrane receptors.